Automatic eradication of bio-related contaminants from handles

ABSTRACT

Techniques for automatically eradicating microorganisms (e.g., germs, bacteria, and/or viruses) from appliance handles using ultraviolet (UV) light are provided. In one aspect, a system for eradicating biological contaminants from a handle on an appliance door is provided. The system includes a UV light emitter for producing UV disinfecting light during a cleaning cycle; and a waveguide coating on the handle, coupled to the UV light emitter, for propagating the UV disinfecting light over a surface of the handle. The system can also include a control module for controlling the UV light emitter; and at least one sensor for providing data to the control module as to when to initiate or halt a cleaning cycle. A method for eradicating biological contaminants from a handle on an appliance door using the present system is also provided.

FIELD OF THE INVENTION

The present invention relates to removing bio-related contaminants fromappliances, and more particularly, to techniques for automaticallyeradicating bio-contaminants such as microorganisms (e.g., germs,bacteria, and/or viruses), nucleic acids (DNA and RNA), proteins such asenzymes (e.g., RNase), and other potentially harmful bio-materials fromappliance handles using ultraviolet (UV) light.

BACKGROUND OF THE INVENTION

Handles on appliances, e.g., refrigerators and microwaves in a home,laboratory equipment, etc. are among the most contaminated (with germs,bacteria, and/or viruses) elements one encounters on a daily basis.Namely, due to frequent contact of appliance user's hands with food(such as raw ingredients) and again with the appliance's handle, and dueto the multiplicity of appliance users (either in residential settings,office settings and/or commercial use as in restaurants or inlaboratories) handles become hubs of germs. According to the Centers forDisease Control (CDC), food-borne diseases cause about 76 millionillnesses, 325,000 hospitalizations, and 5,000 deaths in the UnitedStates each year. A variety of different disease causing microorganisms,such as Escherichia coli and Staphylococcus aureus, can be transmittedby dirty hands. Some other settings where bio-contaminates are a concerninclude: contamination of tests involving nucleic acid amplification,where foreign nucleic acids can contaminate specimens, or where RNasesmay alter tested nucleic acids; and hospital settings, where pathogenicmicroorganisms, especially multi-drug resistant bacteria, as well asspores, may be transferred from one patient to another through theenvironment, with contact of patients or medical personnel with handlesbeing an important way of transmission.

Disinfecting wipes are effective in eliminating some types ofmicroorganisms. However, these are too cumbersome for regular use, andcan pose environmental concerns. Users can wear gloves to reduce thespread of germs. However, if the gloves themselves come in contact withcontaminates or germs, their efficacy becomes negligible. Regular use ofgloves is also cumbersome, and impractical in certain setting such as ina household. Other measures have been proposed, such as the use ofpedals or other foot activated means to operate appliances. Yet, closureof the door, cover, or lid is still performed using the handle, and thepedal is not amendable for all appliances.

Thus, there is a need for an effective mechanism to eradicatebio-related contamination from the surface of appliance door handles.

SUMMARY OF THE INVENTION

The present invention provides techniques for automatically eradicatingbio-contaminants from appliance handles using ultraviolet (UV) light. Inone aspect of the invention, a system for eradicating biologicalcontaminants from a handle on an appliance door is provided. The systemincludes a UV light emitter for producing UV disinfecting light during acleaning cycle; and a waveguide coating on the handle, coupled to the UVlight emitter, for propagating the UV disinfecting light over a surfaceof the handle. The system can also include a control module forcontrolling the UV light emitter; and at least one sensor for providingdata to the control module as to when to initiate or halt a cleaningcycle.

In another aspect of the invention, a method for eradicating biologicalcontaminants from a handle on an appliance door is provided. The methodincludes the steps of: monitoring a state of the appliance door aseither opened or closed; and initiating a cleaning cycle when theappliance door is closed by producing UV disinfecting light andpropagating the UV disinfecting light over a surface of the handle usinga waveguide coating on the handle. The cleaning cycle can be haltedwhenever a user approaches the handle.

A more complete understanding of the present invention, as well asfurther features and advantages of the present invention, will beobtained by reference to the following detailed description anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary system for automaticallyeradicating bio-related contaminants from appliance handles according toan embodiment of the present invention;

FIG. 2 is a diagram illustrating an exemplary methodology forautomatically eradicating bio-related contaminants from appliancehandles (e.g., using the system of FIG. 1) according to an embodiment ofthe present invention;

FIG. 3 is a diagram illustrating UV disinfecting light being propagatedthrough a waveguide coating that wraps around the handle according to anembodiment of the present invention;

FIG. 4 is a schematic diagram illustrating UV disinfecting light beingpropagated through a waveguide coating from a UV source to a UV detectoraccording to an embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating localized leakage of UVdisinfecting light at the site of a microorganism on the handleaccording to an embodiment of the present invention;

FIG. 6A is a side-view diagram illustrating a revolving cover being usedto cover the handle during a cleaning cycle according to an embodimentof the present invention;

FIG. 6B is a side-view diagram illustrating the revolving cover havingbeen retracted into its housing once the cleaning cycle has beencompleted (or has been halted) according to an embodiment of the presentinvention;

FIG. 7 is a diagram illustrating a sliding cover which can be used tocover the handle during a cleaning cycle according to an embodiment ofthe present invention; and

FIG. 8 is a diagram illustrating an exemplary apparatus for performingone or more of the methodologies presented herein according to anembodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Provided herein are techniques to eradicate bio-related contamination(such as microorganisms (e.g., germs, bacteria, and/or viruses), nucleicacids (DNA and RNA), proteins such as enzymes (e.g., RNase), and otherpotentially harmful bio-materials) from the surface of appliance doorhandles using ultraviolet (UV) light. See, for example, FIG. 1 whichprovides an overview of the present system 100 for automaticallyeradicating bio-related contaminants from appliance handles. Accordingto an exemplary embodiment, system 100 is contained within the applianceitself. Thus, a notable advantage is that it enables use of theappliance's power feed. Therefore, the availability of power to run thesystem is not an issue. The application of the present techniques toappliance handles is merely one example. The techniques described hereincan be used in a variety of different settings for eradicatingbio-contaminants, such as hospital bedsides, laboratory fume hoodsurfaces, incubators (for microorganisms/cells) or other surfaces (e.g.,for preparing food, handling biological samples, preparing medications,mats, etc.). The access to a constant power source (as is the case foran appliance) is, in these other settings as well, also an advantage. Asshown in FIG. 1, system 100 includes a UV light emitter 102 under thecontrol of a control module 104, and a variety of sensors 106, 108, 110,etc. that provide data to the control module 108. It is notable that theconfiguration of system 100 shown in FIG. 1 is merely an example, andvariations to this design are contemplated herein. For instance,multiple UV light emitters (for example in the case where an appliancehas multiple doors and therefore handles) and/or other sensors not shownin FIG. 1 may be employed. For instance, light sensors might be employedto detect when the room lights have been switched off which can serve asan indicator that the user has left the room, and thus the appliancehandle is not in use and a cleaning cycle might be initiated. System 100can be configured to include all commercially available sensors.

During operation, the UV light emitter 102 (located proximal to the doorhandle(s)—see below) automatically shines UV disinfecting light.Preferably, this occurs after each use of the door. Namely, it isdesired that after the user opens and then closes the appliance door,the door's handle is disinfected via the UV light from the emitter 102.

A door sensor 106 serves as an indicator to control module 104 that thedoor has been closed. For example, door sensor 106 can be simple contactsensor or door opening sensor that detects when the appliance door is ina closed state. A contact sensor, for example, can detect when the dooris in contact with its frame (as opposed to when the door is swung openand not in contact with the frame).

Control module 104 monitors the door state (i.e., open or closed), andonce the door state changes, from open to closed, a cleaning cycle isinitiated whereby the control module causes the UV light emitter 102 toshine UV disinfecting light on the door handle. In case a user decidesto approach the door handle during a cleaning cycle, a proximity sensor110 will alert the control module 104 (i.e., that the user's hand is inthe proximity of the handle), which will immediately halt the cleaningcycle by deactivating the emitter 102 until the cleaning cycle ispermitted to resume (e.g., once the user has moved away and the door hasbeen closed). As will be described in detail below, revolving orretracting covers may be employed to shield the handle during a cleaningcycle. In that case, the proximity sensors 110 can also be used toindicate to the control module 104 when to retract the cover in responseto a user approaching the handle.

Also, as will be described in detail below, the UV light is preferablypropagated over the surface of the handle using a waveguide coating. AUV sensor/detector 108 can be coupled to the waveguide (e.g., oppositeto the emitter) to detect how much, if any, UV light is escaping thewaveguide. If a user were to grab the handle during a cleaning cycle,this can be detected via the UV detector and the cleaning cycleinstantly halted.

The general operation of system 100 is depicted in methodology 200 ofFIG. 2. In step 202, the door state (i.e., open or closed) is monitored,e.g., via control module 108. When it is determined in step 204 that thedoor state has changed, and in step 206 that the door of the applianceis closed, e.g., via the door sensor 104, then in step 208 the controlmodule initiates a cleaning cycle of the door handle, e.g., via UVdisinfecting light from emitter 102. Otherwise, the control modulecontinues to monitor the door state.

In step 210, a (e.g., revolving or sliding) cover can move over thehandle for the duration of the cleaning cycle in order to prevent usersfrom grabbing the handle. Various configurations of the cover aredescribed in detail below. Additionally, in step 212 the user may bealerted that a cleaning cycle is in progress. For instance, a red lightindicator can be turned on to indicate that disinfection is in progress.The red light indicator can be turned green once disinfection iscompleted.

As shown in FIG. 2, if it is determined during a cleaning cycle in step214 that a user has grabbed the handle (e.g., via touch sensor 106)and/or is in proximity to the appliance (via a proximity sensor), thenin step 216 the cleaning cycle is halted until the user has closed thedoor again (and has moved away from the appliance). Otherwise, thecleaning cycle is continued in step 218, e.g., for its given duration,and the control module continues to monitor the door state to detect thenext time the door is opened/closed.

Given the above overview of the present techniques, some exemplaryconfigurations for system 100 are now described. According to anexemplary embodiment, the UV disinfecting light from emitter 102 ispropagated through a waveguide that wraps around the handle. Forinstance, the waveguide can be embodied as a coating on the handle. SeeFIG. 3.

As shown in FIG. 3, the door handle is coated all-around with a layerthat operates as a waveguide (labeled “Waveguide coating”). Suitablewaveguide coatings include, but are not limited to, glass, polymercoatings (in particular polymers resistant to UV light), and some metaloxides with bandgap transparent to UV. For instance, a glass such assilicon dioxide SiO₂ is particularly well suited for the presentprocess, as is a metal oxide such as aluminum oxide. The waveguidecoating material needs to be resistant to UV light, and preferably alsoresistant to materials commonly used in cleaning appliances, such asdetergents, disinfectants including those containing solvents such asalcohol, bleach, and chlorhexidine. By way of example only, thewaveguide coating can be applied to the handle by dipping coating,spraying, etc. to a thickness of from about 1 micrometer (μm) to about 5μm, and ranges therebetween. Thicker coatings can also be used. One maywant to use a thicker coating, for instance, when the handle has surfaceroughness and a thicker, non-conformal coating would provide a smoothexterior surface for the handle.

In many applications (for example a fiber optics), the waveguide whichcontains the light is the core of the structure, and coatings may beapplied to the waveguide core, e.g., for mechanical reasons. Thewaveguide does not, however, have to be the core per se, and in thepresent embodiments the core is the handle. All that is required is thatthe material outside of the waveguide will have a refractive indexsmaller than that of the waveguide material. In the present case thematerial outside the waveguide is air n=1.0, while the waveguide is,e.g., glass with n=1.5 (or other suitable material—see above). Thehandle is typically made of metal which will reflect all the light backinto the waveguide. The light is guided in the waveguide by a mechanismknown as total internal reflections.

Advantageously, by forming a coating that wraps around the handle, theUV disinfecting light (which is propagated through the waveguidecoating) will have access to all surfaces around the handle. This wouldnot be the case if, for instance, one was to simply shine UV light ontothe handle. Further, the present waveguide coating can be formed (e.g.,by dipping, spraying, etc.—see above) on an ordinary appliance handle.Thus, the present techniques can be implemented in regular appliancemanufacturing processes. The coating needs to wet the handle material toform a film. In cases where the material does not like to wet a surface,it is possible to overcome this by using an adhesion promoter. Forinstance, silanes can be used as adhesion promoters between SiO₂ andpolymers such as polyimides.

FIGS. 4 and 5 illustrate the principles behind the waveguide coating foruse in propagating the UV disinfecting light. As shown in FIG. 4, a UVsource is coupled to one (first) end of the waveguide coating. In thisexample, the UV source may be considered to be the UV light emitter 102of the present system. According to an exemplary embodiment, the UVlight source/emitter is an array of semiconductor light emitting diodesor LEDs, having as an active material gallium nitride (GaN), aluminumnitride (AlN), or alloys thereof such as indium-gallium-aluminum nitride(In_(x)Ga_(1-x)Al_(y)N_(1-y)). The use of LEDs as a UV source has somenotable advantages. For instance, the life time of LEDs can exceed 50years so there is no maintenance (e.g., replacing a UV bulb). Also, LEDsare small and therefore can be easily embedded in tight spaces such atthe base of the handle.

The UV light (from the UV source) that is coupled into the waveguidecoating cannot escape the waveguide due to the large refractive indexdifference between the coating (e.g., a glass coating has a refractiveindex n₁ of about 1.5) and air (which has a refractive index n₂ ofabout 1. As a result, the UV light is internally reflected throughoutthe coating. See FIG. 4.

As shown in FIG. 4, a UV detector is coupled to a (second) end of thewaveguide coating opposite the UV source. Thus, the waveguide coatingpropagates light from the UV source to the UV detector. The UV detectorconstantly monitors the UV power transmitted through the waveguidecoating. When the UV detector detects a power drop, it suggests that UVlight is leaking out of the waveguide coating. UV light leakage isexpected when eradicating microorganisms on the surface of the waveguidecoating/handle. See, for example, FIG. 5. When a microorganism, such asa bacteria, is present at the surface of the waveguide due to the largecontent of water in the bacteria UV light from the waveguide will leakinto the bacteria (water has a high refractive index n₃ of about 1.4),thus effectively eradicating the bacteria. See for example FIG. 5 whereit is shown that UV light leaks through the waveguide coating at thesite of the bacteria. This happens locally, only where bacteria ispresent on the surface. Nucleic acids (RNA and DNA) are also vulnerableto UV radiation. Thus, other microorganisms such as viruses (whichtypically contain at least one of RNA and DNA), can be eradicated fromthe surface of the waveguide coating/handle. Further, viruses are oftenpassed to surfaces (such as the handle in question) by a user touchingthe handle (which causes some humidity to pass from the user's hand tothe handle), and/or the user speaking, coughing, sneezing, etc. (allwhich involve water-containing, e.g., aerosolized, droplets that land onthe handle.

Based on the UV detector, a threshold can be preset such that if thelevel of UV light begin detected drops by more than the threshold amount(which indicates that too much UV light is leaking out of the waveguide)then the UV source is turned off, and the cleaning cycle is halted (seestep 212 of methodology 200 of FIG. 2—above). By way of example only, ifthe amount of UV light detected drops by more than about 10%, then theUV source is shut off halting the cleaning cycle.

One reason the waveguide might become too “leaky” is if the handlebecomes too dirty. For instance, an increased amount of bacteria on thehandle increases the amount of UV light escaping from the waveguidecoating, and thereby reduces the amount of UV light sensed by thedetector. When the threshold is breached, the cleansing cycle will behalted, and the user alerted that the handle should be thoroughlycleaned by the user, e.g., wipe it with a cleaning cloth. Only when theamount of UV light reaching the detector is restored to acceptablelevels (i.e., leaking is below the threshold) can the cleaning cyclecommence again. Any type of visual and/or audible notification may beused to alert the user. For instance, a message could be provided on adisplay of the appliance, such as “Cleaning needed” or “Handle dirty,please wipe down.” Similarly, these commands might be present on acontrol panel of the appliance and illuminated or otherwise highlightedto catch the user's attention.

Preferably, a cleaning cycle is run when no one is present. See, forexample, the above-described warning light indicators that alert usersthat a cleaning cycle is being run, sensors to detect that no one is inthe room, etc. To add an extra level of protection, the other varioussensors and fail-safe mechanisms described above, such as touch andproximity sensors, can be used to halt the cleaning cycle in the eventthat a user, despite the warnings, approaches the handle. To provide yetanother level of safety, an ultrafast “circuit breaker” safety featurecan be employed. This feature is now described.

Another reason the waveguide coating might become too leaky is if theuser, despite being alerted that cleaning is in progress (see step 212of methodology 200 of FIG. 2), still grabs the handle. In that case, theUV light source is immediately and automatically turned off. The drop inthe UV light can be detected on a time scale shorter than a microsecond,and shutting down the UV light source can also be done on the same timescale. As a result of this ultrafast “circuit breaker” safety feature,the exposure to UV light is minimal and is designed to be a smallfraction of the exposure limits allowed by National Institute forOccupational Safety and Health (NIOSH). For additional safety, aproximity sensor can be used to shut down the UV source when a person'shand is approaching the door handle. It is notable, however, that onlyupon physical contact of the hand with the waveguide coating can UVlight leak, since the UV light cannot escape the waveguide coating aslong as it is surrounded by air.

As described above, a cover can be employed that is actuated over thehandle during a cleaning cycle. This will help prevent users fromgrabbing the handle while it is being cleaned via the above-describedwaveguide coating. In one exemplary embodiment, the cover revolvesaround the handle to cover the handle during a cleaning cycle and toexpose the handle once cleaning is completed (or halted). See FIGS. 6Aand 6B. Specifically, as shown in FIG. 6A, during a cleaning cycle, thecover (which can revolve in and out of a cover housing behind thehandle) surrounds the handle. As described above, the cover can beengaged when the cleaning cycle is initiated (see step 210 ofmethodology 200 of FIG. 2). This will shield the handle during thecleaning cycle. Further, a red indicator light, or other form ofalerting the user, may be turned on to indicate that a cleaning cycle isin progress.

As shown in FIG. 6B, when the cleaning cycle is completed (or halted),the cover retracts back into its housing, exposing the handle which canthen be gripped by the user to open the door. The indicator lightchanges to green letting the user know it is okay to use the handle.Naturally, the revolving cover may retract when the cleaning cycle hasrun to completion (see step 218 of methodology 200 of FIG. 2). However,as described above, the cleaning cycle might also be halted if the userdecides to grab the handle during the cleaning cycle. According to anexemplary embodiment, proximity sensors (see above) are employed thatdetect the user is approaching the handle, the cleaning cycle isimmediately halted, and the cover is retracted into its housing. Onlywhen (via the proximity sensors) it is determined that the user hasmoved away from the appliance, will the cover rotate back over thehandle, and the cleaning cycle recommence until completion.

Another configuration anticipated herein for the cover mechanism isshown in FIG. 7. In this example, the cover is a sliding (as opposed torotating) cover. Namely, as shown in FIG. 7, this cover, when actuated(e.g., during a cleaning cycle) slides over and covering the handle.When the cleaning cycle is complete (or halted), the cover can retractby sliding to expose the handle, which can then be used to open thedoor. Namely, in the same manner as described above with respect to therevolving cover, proximity sensors can be employed to determine when auser is approaching the handle, at which time the cleaning cycle can behalted and the cover retracted to permit the user to grab the handle.Only when it is determined that the user has moved away from theappliance, will the cover slide back over the handle, and the cleaningcycle recommence until completion.

Turning now to FIG. 8, a block diagram is shown of an apparatus 800 forimplementing one or more of the methodologies presented herein. By wayof example only, apparatus 800 is representative of the control module104 (of system 100 of FIG. 1) and can be configured to implement one ormore of the steps of methodology 200 of FIG. 2.

Apparatus 800 includes a computer system 810 and removable media 850.Computer system 810 includes a processor device 820, a network interface825, a memory 830, a media interface 835 and an optional display 840.Network interface 825 allows computer system 810 to connect to anetwork, while media interface 835 allows computer system 810 tointeract with media, such as a hard drive or removable media 850.

Processor device 820 can be configured to implement the methods, steps,and functions disclosed herein. The memory 830 could be distributed orlocal and the processor device 820 could be distributed or singular. Thememory 830 could be implemented as an electrical, magnetic or opticalmemory, or any combination of these or other types of storage devices.Moreover, the term “memory” should be construed broadly enough toencompass any information able to be read from, or written to, anaddress in the addressable space accessed by processor device 820. Withthis definition, information on a network, accessible through networkinterface 825, is still within memory 830 because the processor device820 can retrieve the information from the network. It should be notedthat each distributed processor that makes up processor device 820generally contains its own addressable memory space. It should also benoted that some or all of computer system 810 can be incorporated intoan application—specific or general—use integrated circuit.

Optional display 840 is any type of display suitable for interactingwith a human user of apparatus 800. Generally, display 840 is a computermonitor or other similar display.

Although illustrative embodiments of the present invention have beendescribed herein, it is to be understood that the invention is notlimited to those precise embodiments, and that various other changes andmodifications may be made by one skilled in the art without departingfrom the scope of the invention.

What is claimed is:
 1. A method for eradicating biological contaminantsfrom a handle on an appliance door, the method comprising the steps of:monitoring a state of the appliance door as either opened or closed; andinitiating a cleaning cycle when the appliance door is closed byproducing ultraviolet (UV) disinfecting light and propagating the UVdisinfecting light over a surface of the handle using a waveguidecoating on the handle; detecting the UV disinfecting light beingtransmitted through the waveguide coating; halting the cleaning cyclewhen the UV disinfecting light being transmitted through the waveguidecoating drops by more than a preset threshold amount indicating that thehandle is too dirty; and alerting a user that the handle should becleaned by the user.
 2. The method of claim 1, wherein the UVdisinfecting light is produced by an emitter coupled to the waveguidecoating.
 3. The method of claim 1, further comprising the step of:determining the state of the appliance door using a door sensor.
 4. Themethod of claim 1, further comprising the step of: actuating a cover toshield the handle during the cleaning cycle.
 5. The method of claim 4,further comprising the step of revolving the cover over the handle. 6.The method of claim 4, further comprising the step of: sliding the coverover the handle.
 7. The method of claim 1, further comprising the stepof: alerting users that the cleaning session has been initiated.
 8. Themethod of claim 1, further comprising the step of: halting the cleaningcycle whenever the user approaches the handle.
 9. The method of claim 8,further comprising the step of: determining that the user is approachingthe handle using a proximity sensor.
 10. The method of claim 1, furthercomprising the step of: determining how much of the UV disinfectinglight is leaking from the waveguide coating using a UV detector, whereinthe UV detector is coupled to an end of the waveguide coating oppositethe UV light emitter.